1. Field of the Invention
This invention relates to a rotational power transmission device having planetary gears, and in particular to a rotational power transmission device that is able to selectively output normal and reverse rotations at an equal speed from a rotational output shaft arranged coaxially with a rotational input shaft.
2. Prior Art Description
There has known a rotational power transmission device that has rotational input and output shafts arranged coaxially and is constituted so that rotational output of normal and reverse directions can be obtained from the rotational output shaft. Typically, this type of device has a gear train associated with a clutch mechanism for changing the rotational direction of input rotation.
An object of this invention is to provide a rotational power transmission device having the above function by making use of planetary gears in a manner that it is constituted compact in structure.